The present technology relates to an illumination unit and a display unit each of which includes a light modulation device exhibiting a scattering property or transparency with respect to light.
In recent years, improvements in image quality and energy conservation of liquid crystal displays have been accelerated, and systems achieving an improvement in dark-room contrast by modulating light intensity in a partial region of a backlight have been proposed. As a main technique of achieving an improvement in dark-room contrast, some of light-emitting diodes (LEDs) used as light sources of a backlight are driven to modulate backlight light based on a display image. Moreover, in large-screen liquid crystal displays, as with small-screen liquid crystal displays, thinner displays have been increasingly demanded; therefore, attention has been given not to a system in which cold cathode fluorescent lamps (CCFLs) or LEDs are disposed directly below a liquid crystal panel, but to an edge light system in which a light source is disposed on an edge of a light guide plate.
The applicant of the present application has achieved a partial drive in which light intensity in a partial region of the backlight is modulated, and has disclosed the partial drive in, for example, PTL 1. In PTL 1, to achieve the above-described partial drive, a polymer dispersed liquid crystal (PDLC) is used. In PTL 1, the PDLC is formed by mixing a liquid crystal material and a low-molecular material having orientation and polymerizability, and causing phase separation by ultraviolet irradiation, and is a composite layer in which the liquid crystal material is dispersed in a polymer material with a streaky structure. The PDLC is classified into a horizontal alignment type, a vertical alignment type, and an isotropic type based on orientation under no voltage application. Among them, the horizontal alignment type PDLC is the most suitable for the backlight, because high luminance and high contrast are obtainable.